Commutator for motors.



A. J. PFAPF.

GOMMUTATOR FOR MOTO APPLICATION FILED A Patented Feb. 16, 1909.

iirients.

UNITED STATES PA ilQIiif ANDREW J. PFAFF, OI! ST. LOUIS, MISSOURI,ASSIGNOR 'lO EMERSON ELECTRIC MANUFACTURING GOB'IPANY, OF ST. LOUIS,MISSOURI, A CORPORATION OF MISSOURI.

COMMUTATOB FOE MOTORS.

Specification of Letters Patent.

Patented Feb. 16, 1909.

Application filed April 29, 1998. Serial No. 429,854.

T 0 all whom it may concern:

Be it known that I, ANDREW J. PFAFF, a citizen of the United States,residing at St. Louis, Missouri, have invented a certain new and usefulImprovement in Commutators for Motors, of which the following is a full,clear, and exact description, such as will enable others skilled in theart to which it appertains to make and use the same, reference being hadto the accompanying drawings, forming part of this specification, inwhich- Figure l is a longitudinal sectional view of a commutatorconstructed in accordance with my invention; Fig. 2 is a cross sectionalview taken on the line 2-2 of Fig. 1; and Fig. 3 is a detail sectionalview of a modified form of my invention.

This invention relates to motors, and particularly to the commutators ofmotors.

The main object of my invention is to i provide a commutator of simpleconstruction in which the head of the commutator is provided with ringsof hard and smooth insulating cement arranged adjacent to the ends ofthe segments that are mounted on said head.

Referring to the drawings which illustrate the preferred form of myinvention, A designates the head of a commutator, and B desi nates thecommutator segments mounted on said head and provided with projectingend portions that extend into undercut recesses in the head, thesegments being insulated from each other and from the head by means ofmica C or some other suitable insulating material. Rings 1 of insulatingcement are mounted on the head adjacent the ends of the segments so asto prevent carbon and metal dust from accumulating on the head at theends of the segments and thus causing short circuits between the seg Iprefer to form these rings 1 from some suitable insulating cement whichcan be run into an approximately dovetailed groove formed partly in theouter surfaceof the head A of the commutator and partly in the ends ofthe segments and then be machined down to roduce a smooth surface. Onekind of insu ating cement that I have found to be very Well adapted forthis pur-w various other insulating cements could be used for thispurpose. These rings are oil and heat proof and as they have hard smoothsurfaces they can be wiped off and iept clean easily so that dirt cannotcollect at the ends of the segments and thus shortcircuit same.

Instead of using a cement ring of the shape shown in Fig. 1 I can use acement ring 2 provided with an upwardly projecting flange 2 that is setinto the vertical end faces 01' the commutator segments, as shown inFig. 3. I prefer to provide the ring shown in Fig. 3 with a curvedsurface 3 at the junction r of the horizontal and vertical portions soas to eliminate a corner in which dirt might collect.

Having thus described my invention, what I claim as new and desire tosecure by Let ters Patent is:

I. A commutator provided with a head, segments mounted on said head, andrings of self-hardening insulating material arranged in grooves formedpartially in the outer surface of the head and in the ends of thesegments; substantially as described.

2. A commutator provided with a head, segments mounted on said head, andinsulating rings set into the outer surface of the head and in the endportions of the segments and consisting of hard molded material; sub- Estantially as described.

i 3. A commutator provided with a head. i segments mounted on said headand having projecting end portions that extend into undercut recesses insaid head, and rings of g molded insulating material engaging said sements and lying flush with the outer surl A commutator provided with ahead, segments mounted on said head and pro- 'i jcctinf: outwardlytherefrom, the outer sur 1 face of the head and the end portions of thesegments being cut away so as to form approximately dove-tailed grooves,and rings l of molded insulating material arranged in 1 said grooves;substantially as described.

5. A commutator provided with a head, Esegments mounted on said head andpro i jecting outwardly therefrom, and rings of fself-harde ninginsulating material lying flush l with the outer surface of thehead andextending into undercut grooves formed in the end portions of thesegments and in the outer surface of the head; substantially asdescribed.

6. A commutator provided with a head,

segments mounted on said head andprojecting outwardly therefrom and aring of insulating material filling a groove in the outer surface ofsaid head and having a radially disposed flange that is set into theends of the segments; substantially as described.

7. A commutator provided with a head, segments mounted on said head andprojecting outwardly'therefrom, a ring of hard and smooth insulatingmaterial arranged in a signature in t groove formed ,inthe outer'surfaceof said body 0 the ring; substantially as described.

whereof I hereunto afiix my e presence of two Witnesses, this twentyseventh day of April 1908 ANDREW J. PFAFF.

-' Intestimoni Witnesses:

WELLs L. CHURCH, GEORGE BAKEWELL:

